Joule, James Prescott


Joule, James Prescott

▪ English physicist
born December 24, 1818, Salford, Lancashire [now in Greater Manchester], England
died October 11, 1889, Sale, Cheshire

      English physicist who established that the various forms of energy—mechanical, electrical, and heat—are basically the same and can be changed, one into another. Thus he formed the basis of the law of conservation of energy (energy, conservation of), the first law of thermodynamics.

      Joule studied with the noted English chemist John Dalton at the University of Manchester in 1835. Describing “Joule's law” in a paper, On the Production of Heat by Voltaic Electricity (1840), he stated that the heat produced in a wire by an electric current is proportional to the product of the resistance of the wire and the square of the current. In 1843 he published his value for the amount of work required to produce a unit of heat, called the mechanical equivalent of heat. He used four increasingly accurate methods of determining this value. By using different materials, he also established that heat was a form of energy regardless of the substance that was heated. In 1852 Joule and William Thomson (later Lord Kelvin) discovered that when a gas is allowed to expand without performing external work, the temperature of the gas falls. This “ Joule-Thomson effect” was used to build a large refrigeration industry in the 19th century. The value of the mechanical equivalent of heat is generally represented by the letter J, and a standard unit of work is called the joule.

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Universalium. 2010.

Look at other dictionaries:

  • Joule,James Prescott — Joule (jo͞ol, joul), James Prescott. 1818 1889. British physicist who established the mechanical theory of heat and discovered the first law of thermodynamics. * * * …   Universalium

  • Joule , James Prescott — (1818–1889) British physicist Joule, the son of a brewer from Salford, received little formal education, was never appointed to an academic post, and remained a brewer all his life. He began work in a private laboratory that his father built near …   Scientists

  • Joule, James (Prescott) — born Dec. 24, 1818, Salford, Lancashire, Eng. died Oct. 11, 1889, Sale, Cheshire English physicist. After studying under John Dalton, in 1840 he described Joule s law, which stated that the heat produced in a wire by an electric current is… …   Universalium

  • Joule, James (Prescott) — (24 dic. 1818, Salford, Lancashire, Inglaterra–11 oct. 1889, Sale, Cheshire). Físico inglés. Después de estudiar bajo la guía de John Dalton, en 1840 describió la ley de Joule, la cual afirmaba que el calor producido en un alambre por una… …   Enciclopedia Universal

  • Joule, James Prescott — ► (1818 89) Físico británico. Estudió el efecto calorífico de la corriente eléctrica y encontró la equivalencia mecánica del calor …   Enciclopedia Universal

  • JOULE, JAMES PRESCOTT —    a celebrated physicist, born at Salford; was a pupil of Dalton s, and devoted his time to physical and chemical research; made discoveries in connection with the production of heat by voltaic electricity, demonstrated the equivalence of heat… …   The Nuttall Encyclopaedia

  • James Prescott Joule — James Joule James Prescott Joule (Salford, Mánchester, 24 de diciembre de 1818 Salford, 11 de octubre de 1889) fue un físico inglés. Fue u …   Wikipedia Español

  • James Prescott Joule — James P. Joule James Prescott Joule (* 24. Dezember 1818 in Salford bei Manchester; † 11. Oktober 1889 in Sale (Greater Manchester), Aussprache: dʒuːl[1]) war ein britischer Physiker …   Deutsch Wikipedia

  • James Prescott Joule — Pour les articles homonymes, voir Prescott et Joule (homonymie). James Prescott Joule James Prescott Joule Naissance …   Wikipédia en Français

  • James Prescott Joule — Infobox Scientist name = James Prescott Joule image width = 200px caption = James Joule English physicist birth date = birth date|1818|12|24 birth place = Salford, Lancashire, England death date = death date and age|1889|10|11|1818|12|24 death… …   Wikipedia


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